I drove the BQ25570-evm board.
When VIN-DC = 600 mV (I = 1 mA ) is entered as Power Supply,
EN pin = 0, and VOUT EN pin = 1.
The result was that the VSTOR voltage rose to 4.2V, and the VOUT output was 1.8V. I think I'm out of cold start mode very well.
Later, I tried to charge the super capacitor, the battery storage element, by connecting it to the VOUT terminal.
Let me introduce you to the supercapacitor I'm connected to.
1. 70F, 2.1V Super Capacitor
The PS voltage dropped to half 300 mV and entered the CC mode.
The VOUT output connected to the supercapacitor was 1.1V.
It was not charged and kept at 1.1V.
2. 22F, 2.3V Super Capacitor
Similarly, the PS voltage dropped to 500 mV and entered CC mode, with the VOUT output connected to the supercapacitor at 900 mV.
It was not charged and was maintained at 900 mV.
3. 100F, 2.7V Super Capacitor
Similarly, PS's voltage decreased and entered CC mode.
VOUT output that connects super capacitors came out 300mV.
The super capacitor was not charged and maintained at 300 mV.
4. 20F, 3.8V Super Capacitor
This time the PS voltage was maintained and the CV mode was maintained.
The VOUT output that connects the supercapacitor came out at 2.4V.
This supercapacitor wasn't charged either.
I don't know why these results came out.
In my opinion, there is only a time difference but in the end these four types of super capacitors must be charged up to 1.8V, the basic output of the board.
But when I connected these super capacitors to the board,
PS's voltage drops and enters CC mode.
I don't know why this is happening.
And I don't know why super capacitors are not charging
In addition, Super Capacitor No. 4 maintained the voltage at PS and CV mode, but was not charged.
I don't know why the results of CC mode and CV mode 1, 2, 3 and 4 are different.
Is it because of the board's internal resistance?
Or is it because of the super capacitor's F, DC?
I want to know why it appears like this.
PS. And, then, when 600 mV ( 1 mA ) power is entered into the board, how can the supercapacitor be properly charged
But I don't know why when I connected one, two, three super capacitors to the board,
I don't know if PS's voltage drops and enters CC mode.
I don't know why super capacitors are not charging
